1. Technical Field of the Invention
The present invention relates to a wireless communication system for transmitting and receiving a radio signal carrying a voice signal indicative of a speaker's voice, and more particularly to a wireless communication system comprising at least one wireless microphone for transmitting a radio signal carrying a voice signal and a wireless receiving unit for receiving the radio signal carrying the voice signal transmitted by the wireless microphone in a local communication area to ensure reliable communication based on a channel, a gain, and other operation conditions inputted into the wireless microphone.
2. Description of the Related Art
Up until now, there have been proposed a wide variety of wireless communication systems of this type one typical example of which is shown in FIG 12. The conventional wireless communication system is shown in FIG. 12 as comprising at least one wireless microphone for receiving a speaker's voice while transmitting a radio signal carrying a voice signal indicative of the speaker's voice and a wireless receiving unit for receiving the radio signal carrying the voice signal transmitted by the wireless microphone.
The wireless microphone includes sound signal receiving means 11 for receiving a speaker's voice while converting the speaker's voice into a voice signal, a sound signal amplifier 12 for amplifying the voice signal received by the sound signal receiving means 11, a channel selecting switch 27 having signal channels to select one of the signal channels, storing means 19 for storing information on frequencies of the radio signals in association with the signal channels, deciding means 18 for deciding the frequency of the radio signal in response to the signal channels selected by the channel selecting switch 27 with reference to the information stored by the storing means 19, modulating means 13 for modulating the radio signal to produce the radio signal carrying the voice signal amplified by the sound signal amplifier 12, controlling means 16 for allowing the modulating means 13 to generate the radio signal in association with the signal channel selected by the channel selecting switch 27, a radio signal amplifier 14 for amplifying the radio signal carrying the voice signal produced by the modulating means 13, and transmitting means 15 for transmitting the radio signal carrying the voice signal amplified by the radio signal amplifier 14.
The channel selecting switch 27 has a plurality of switch elements to be selectively operated for transmitting respective radio signals to the transmitting means. The switch elements are arranged in the wireless microphone which has a cover member to cover switch elements. The structure of the microphone and the switch elements thus constructed requires an operator to open and close the cover member before the switch elements are selectively operated to change the signal channels. The operator finds it laborious to perform such an opening and closing operation before selecting the desirable signal channels. On the other hand, there is no wireless communication system comprising a receiving unit which can select the signal channels in cooperation with the wireless microphone. If the conventional wireless communication systems are installed in the vicinity to each other, as shown in FIG. 11, the radio signal outputted from one of the wireless communication system tends to interfere with the radio signal from the other of the wireless communication systems and therefore leads to deteriorate the productivity of the speaker's voice when the switch elements are mistaken to be operated by the operator.
The previously mentioned conventional wireless communication system thus constructed as previously mentioned encounters such problems that the wireless microphone makes it laborious to open and close the cover member before the switch elements are selectively operated to change the signal channels, and that the wireless receiving unit of one of the conventional wireless communication system tends to receive the radio signals transmitted by the wireless microphones of the other of the conventional wireless communication systems and therefore leads to deteriorate the productivity of the speakers voice.